Chinese Journal of Schistosomiasis Control

Malaria was one for the most serious communicable diseases in China. Following the concerted efforts for decades, remarkable achievements have been gained for malaria control in China. Since the national malaria elimination programme was initiated in China in 2010, local malaria transmission was rapidly interrupted, with zero indigenous malaria case reported for the first time in the country in 2017, and the country will undergo the certification of malaria elimination by WHO. Currently, however, malaria remains hyper-endemic across the world. In China, there are more than 2 000 overseas imported malaria cases each year, and prevention of re-establishment of imported malaria will become the major task in future malaria control activities. Here by, we analyze the main challenges in the prevention of re-establishment of imported malaria in China, and propose the corresponding countermeasures, so as to provide insights into the consolidation of malaria elimination achievements. ［摘要］ 疟疾曾是我国流行最严重的传染病之一。在几代人不懈努力下, 我国疟疾防控成效显著。自 2010 年我国启动《中国消除疟疾行动计划 (2010—2020 年) 》后, 迅速阻断了本地疟疾传播, 2017 年首次在全国范围内实现了本地病例零报告, 即将迎接 WHO 消除疟疾认证。但目前全球疟疾流行依然非常严重, 我国每年仍有 2 000 多例境外输入性疟疾病例, 防止输入再传播将成为下阶段我国疟疾防控工作的主要任务。本文分析了我国防止疟疾输入再传播工作中面临的主要挑战, 并提出相应的应对策略, 从而为巩固消除疟疾成果提供参考。

GD Zhu

Q. Gao

J. Cao

Zhongguo xuexichongbing fangzhi zazhi

[Challenges and countermeasures in prevention of re - establishment of imported malaria in China].

[中国输入性疟疾再传播的挑战与对策]。

OBJECTIVE
To evaluate the effect of the water conservancy schistosomiasis control projects in rivers and estuaries connecting with the Yangtze River on Oncomelania snail control.


METHODS
Three water conservancy schistosomiasis control projects of Laobianmin River, Panjia River and Bianmin River were chosen for the objects of the study. The concrete slope protection and the overflow dam, the concrete slope protection and the check sluice, and the simple concrete slope protection were built respectively in above mentioned three rivers. The changes of the area with snails and density of snails were investigated before and after the interventions, and the results were compared among the three projects.


RESULTS
In the condition of the routine snail control with the molluscicide, the snails were eliminated in the main riverway of the Laobianmin River, but the snails still existed in the target protected area (tributaries of the river and irrigation areas); the snails were eliminated in the Panjia River and its irrigation areas; in the Bianmin River, the areas with snails dropped by 89.22% in the main river and still remained in the tributaries and irrigation areas after the project implementation.


CONCLUSIONS
The sluice and overflow dam more contribute to control and eliminate snails in the project areas and the target protected areas in the rivers and estuaries connecting with the Yangtze River. The priority of consideration should be given to the water level control and prevention of snail spreading in the water level instability rivers connecting with the Yangtze River.

Z. Huang

Zhaoxu Zhu

D. Hang

Wei Li

Shi-jun Chen

Ke-wei Zhang

Zheng Zhang

Shuijing Li

Xun Peng

Zhongguo xue xi chong bing fang zhi za zhi = Chinese journal of schistosomiasis control

[Effect of water conservancy schistosomiasis control projects in rivers and estuaries connecting with the Yangtze River on Oncomelania snail control].

Objective To analyze the endemic situation of schistosomiasis in a national surveillance site of Yangzhong City, so as to provide the scientific evidence for adjusting the local schistosomiasis control strategy and consolidating the control achievements. Methods According to the National Schistosomiasis Surveillance Scheme (2014 version), the snail status, Schistosoma japonicum infections in humans and livestock and wild feces contamination were monitored in Zhinan Village, a national schistosomiasis surveillance site in Yangzhong City from 2015 to 2018. Results Theareasofsnailhabitatsreducedfrom 8.10 hm 2 in 2015 to 2.72 hm 2 in 2018, and the mean density of living snails decreased from 0.27 snails/0.1 m 2 in 2015 to 0.07 snails/0.1 m 2 in 2018 in Zhinan Village; however, no S. japonicum infections were identified in snails during the period from 2015 to 2018. Serological testing for S. japonicum infections was performed in 2 034 local populations and 858 mobile populations from 2015 to 2018, and the sero-prevalence of S. japonicum human infections was 0.59% to 1.98%, with no egg-positives detected. A total of 79 goats were detected for S. japonicum infections from 2015 to 2018, and no egg-positives were found. In addition, no other livestock was found in Zhinan Village from 2015 to 2018, and no wild feces were found in snail habitats. Conclusion A great success has been achieved in schistosomiasis control in Yangzhong City; however, there are still snails breeding in the city. Monitoring of the risk factors pertaining to schistosomiasis transmission should be further intensified to consolidate the control achievements. ［摘要］ 目的 分析扬中市国家血吸虫病监测点疫情, 为完善当地血吸虫病防治对策和巩固防治成效提供科学依据。 方法 按照《全国血吸虫病监测方案 (2014 年版) 》要求, 于 2015-2018 年对扬中市指南村国家血吸虫病监测点进行螺情、 人畜血吸虫病病情、野粪等监测。 结果 2015-2018 年, 扬中市国家血吸虫病监测点有螺面积和活螺平均密度分别由 8.10 hm 2 、0.27 只/0.1 m 2 降至 2.72 hm 2 和 0.07只/0.1 m 2 , 未发现血吸虫感染性钉螺; 开展本地人群和流动人群血清学血吸 虫病筛查 2 034 人·次和 858 人, 血检阳性率为 0.59% ～ 1.98%, 未发现病原学检查阳性者; 共检测羊 79 只, 未发现血吸虫 感染阳性; 未发现牛等其他家畜养殖; 在有螺区域内未发现野粪。 结论 扬中市血吸虫病防治效果显著, 但仍有钉螺孳 生, 应进一步加大对钉螺等血吸虫病传播风险因素监测, 以巩固防治成果。

M. Xiao

RF Wu

HZ Yan

L. Bai

Endemic situation of schistosomiasis in a national surveillance site of Yangzhong City from 2015 to 2018

2015年至2018年扬中市国家级监测点血吸虫病流行情况

Objective To investigate the factors affecting the degradation of niclosamide in the soil, so as to provide the evidence for the assessment of the environmental safety in the field snail control with niclosamide. Methods A high performance liquid chromatography was established for the determination of niclosamide in the field. Then, the degradation of niclosamide was investigated in soils with different moistures (10%, 30%, 50%, 70% and 90%), temperatures [(15 ± 1), (25 ± 1), (35 ± 1) °C], initial concentrations (1, 5, 10 mg/kg) and in sterilized and non-sterilized soils. In addition, the degradation of niclosamide was fitted with the first-order kinetics equation, and the degradation half-life was calculated. Results The niclosamide residues gradually decreased over time in soils with different moistures, and a higher rate of degradation was seen in soils with a higher moisture. The degradation half-life of niclosamide reduced from 4.258 d in the soil with a 10% moisture to 2.412 d in the soil with a 90% moisture. The niclosamide residues gradually decreased over time in soils with different temperatures, and a higher rate of degradation was seen in soils with a higher temperature. The degradation half-life of niclosamide reduced from 4.398 d in the soil with a temperature of (15 ± 1) °C to 2.828 d in the soil with a temperature of (35 ± 1) °C. The degradation half-lives of niclosamide were 3.212, 3.333 d and 3.448 d in soils containing niclosamide at initial concentrations of 1, 5 mg/kg and 10 mg/kg, and > 30 d and 3.273 d in sterilized and non-sterilized soils. Multiple linear regression analysis revealed that soil microorganisms ( P = 0.010), moisture ( P = 0.000) and temperature ( P = 0.002) affected the half-life of niclosamide degradation. Conclusion The degradation of niclosamide in soils fits the first-order kinetics equation, and presence of microorganisms, a high temperature and high moisture may accelerate the degradation of niclosamide in the soil. ［摘要］ 目的 了解灭螺药氯硝柳胺在土壤中降解的影响因素, 为评价氯硝柳胺现场灭螺的环境安全提供参考依据。 方法 建立土壤中氯硝柳胺含量检测的高效液相色谱法, 并分析氯硝柳胺在不同含水量 (10%、30%、50%、70%、90%) 、 不同温度 ([ 15 ± 1) 、 (25 ± 1) 、 (35 ± 1) °C]、不同初始浓度 (1、5、10 mg/kg) 及灭菌和未灭菌土壤中的降解。采用一级反应 动力学方程对氯硝柳胺降解进行拟合, 计算其降解半衰期。 结果 随着时间延长, 氯硝柳胺残留量在不同含水量土壤中 逐渐降低; 土壤含水量越高, 降解越快, 氯硝柳胺在10%～90%含水量土壤中的降解半衰期由4.258 d下降为2.412 d。在不 同温度土壤中, 氯硝柳胺残留量随时间延长而逐渐下降; 温度越高, 氯硝柳胺降解越快, 氯硝柳胺在 (15 ± 1) ～ (35 ± 1) °C 土壤中的降解半衰期由4.398 d下降为2.828 d。1、5、10 mg/kg初始浓度氯硝柳胺在土壤中的降解半衰期分别为3.212、 3.333、3.448 d, 氯硝柳胺在灭菌和未灭菌土壤中的降解半衰期分别为> 30 d和3.273 d。多元线性回归分析发现, 土壤中 微生物 ( P = 0.010) 、含水量 ( P = 0.000) 和温度 ( P = 0.002) 对氯硝柳胺降解半衰期均有影响。 结论 氯硝柳胺在土壤中 的降解符合一级反应动力学方程, 土壤中存在微生物、温度高、含水量增加可促进氯硝柳胺在土壤中的降解。

Y Jia

Y T Xing

J R Dai

G L Qu

Y S Liang

Study on the factors affecting the degradation of niclosamide in the soil

尼可杀米在土壤中降解影响因素的研究

Objective To evaluate the effect of the integrated echinococcosis control program in Ningxia Hui Autonomous Region from 2011 to 2018. Methods A package of integrated interventions were employed for echinococcosis control in 22 counties (districts) of Ningxia Hui Autonomous Region from 2011 to 2018, including screening of human echinococcosis, treatment of echinococcosis patients, deworming of domestic dogs and monitoring of infections, surveillance of echinococcosis in bovines and sheep, health education. The detection of human echinococcosis, seroprevalence of anti- Echinococcus antibody in children at ages of 6 to 12 years, the Echinococcus coproantigen-positive rate in domestic dogs, prevalence of echinococcosis in bovines and sheep, and the awareness of echinococcosis control knowledge were investigated and compared during the period between 2011 and 2018. Results The detection of human echinococcosis appeared a decline tendency in Ningxia Hui Autonomous Region over years during the period from 2011 to 2018 ( χ 2 trend = 82.22, P < 0.05), and the prevalence of human echinococcosis decreased from 0.31% in 2011 to 0.15% in 2018. The seroprevalence of anti- Echinococcus antibody appeared a decline tendency in children at ages of 6 to 12 years over years ( χ 2 trend = 439.64, P < 0.01), and the prevalence of anti- Echinococcus antibody decreased from 6.12% in 2011 to 0.67% in 2018. The Echinococcus coproantigen-positive rate appeared a decline tendency in domestic dogs over years ( χ 2 trend = 260.33, P < 0.05), and the prevalence of anti- Echinococcus antibody decreased from 7.11% in 2011 to 0.75% in 2018. The prevalence of bovine and sheep echinococcosis reduced from 3.26% and 5.08% in 2011 to 1.35% and 0.76% in 2018, and Echinococcus predominantly parasitized in bovine (92.00%) and sheep (93.94%) livers. A total of 63 stool samples were collected from red fox, wolf and badger in Xiji and Haiyuan counties of Ningxia Hui Autonomous Region in 2013 and 2014, with no Echinococcus coproantigen-positives detected, and 107 domestic cats and 3 domestic dogs were dissected in these two counties, with no Echinococcus found. A total of 6 046 wild mice were dissected in Xiji County, Yuanzhou District and Haiyuan County of Ningxia Hui Autonomous Region from 2016 to 2019, and the prevalence of E. multilocularis was 0.31%. The awareness of echinococcosis control knowledge appeared an increasing tendency in Ningxia Hui Autonomous Region over years from 2011 to 2018 ( χ 2 trend = 3 367.97, P < 0.01), and the awareness increased from 21.83% in 2011 to 72.24% in 2018. Conclusion The integrated echinococcosis control program achieves a remarkable effect in Ningxia Hui Autonomous Region, and the transmission of echinococcosis has been preliminarily controlled. However, the echinococcosis transmission risk remains in few regions, and the integrated echinococcosis control program remains to be reinforced. ［摘要］ 目的 评价2011—2018年宁夏回族自治区棘球蚴病综合防治措施实施效果。 方法 2011—2018年在宁夏回 族自治区22个县 (市、区) 开展人群棘球蚴病筛查、病人救治、家犬驱虫与感染监测、牛羊患病监测、人群健康教育为主的 棘球蚴病综合防治措施, 比较2011—2018年人群棘球蚴病检出率、6～12 岁儿童血清抗棘球蚴抗体阳性率、家犬粪棘球 绦虫抗原阳性率、牛羊棘球蚴患病率、人群棘球蚴防治知识知晓率变化。 结果 2011—2018年, 宁夏回族自治区人群棘 球蚴病检出率呈逐年下降趋势 ( χ 2 趋势= 82.22, P < 0.05), 由2011年的0.31%下降到2018年的0.15%; 6～12 岁儿童血清抗 棘球蚴抗体阳性率呈逐年下降趋势 ( χ 2 趋势= 439.64, P < 0.01), 由2011年的6.12%下降至2018年的0.67%; 家犬粪抗原阳 性率呈逐年下降趋势 ( χ 2 趋势= 260.33, P < 0.05), 由2011年的7.11%下降至2018年的0.75%; 牛棘球蚴病患病率由2011年 的3.26%下降至2018年的1.35%, 羊棘球蚴病患病率由2011年的5.08%下降至2018年的0.76%, 且棘球绦虫主要寄生于 牛 (占92.00%) 、羊 (占93.94%) 肝脏。2013—2014年, 在宁夏回族自治区西吉县和海原县采集红狐、狼、獾等野生动物粪 便63份, 未检出阳性粪便; 在2个县累计解剖家猫107只、家犬3只, 均未检出棘球绦虫。2016—2019年, 在宁夏回族自 治区西吉县、原州区和海原县累计解剖野鼠6 046只, 多房棘球绦虫感染率为0.31%。2011—2018年, 宁夏回族自治区人 群棘球蚴病防治知识知晓率呈逐年上升趋势 ( χ 2 趋势= 3 367.97, P < 0.01), 由2011年的21.83%上升至2018年的72.24%。 结论 宁夏回族自治区棘球蚴病综合防治措施实施效果显著, 棘球蚴病流行得到初步控制; 但少数地区棘球蚴病传播风 险依然存在, 仍需加强棘球蚴病综合防治工作。

X L Wu

H J Duan

R T Qi

F Yan

Y R Fu

T B Ma

Evaluation of the effect of the integrated echinococcosis control program in Ningxia Hui Autonomous Region from 2011 to 2018

2011年至2018年宁夏回族自治区包虫病综合防治项目效果评估

OBJECTIVE To evaluate the impact of environmental and climatic factors on the distribution of suitable habitats of Haemaphysalis longicornis, and to predict the potential distribution of H. longicornis under different climate patterns in China. METHODS Data pertaining to the distribution of H. longicornis were retrieved from public literatures. The effects of 19 climatic factors (annual mean temperature, annual mean temperature difference between day and night, isothermality, standard deviation of seasonal variation of temperature, maximum temperature of the warmest month, minimum temperature of the coldest month, temperature annual range, mean temperature of the wettest season, mean temperature of the driest season, mean temperature of the warmest season, mean temperature of the coldest season, annual mean precipitation, precipitation of the wettest month, precipitation of the driest month, coefficient of variance of precipitation, precipitation of the wettest season, precipitation of the driest season, precipitation of the warmest season and precipitation of the coldest season) and 4 environmental factors (elevation, slope, slope aspect and vegetation coverage) on the potential distribution of H. longicornis were assessed using the maximum entropy (MaxEnt) model based on the H. longicornis distribution data and climatic and environmental data, and the potential distribution of H. longicornis was predicted under the RCP 2.6 and 8.5 emissions scenarios. RESULTS Among the environmental and climatic factors affecting the geographical distribution of H. longicornis in China, the factors contributing more than 10% to the distribution of H. longicornis mainly included the precipitation of the driest month (26.0%), annual mean temperature (11.2%), annual mean precipitation (10.0%) and elevation (24.2%). Under the current climate pattern, the high-, medium- and low-suitable habitats of H. longicornis are 1 231 900, 1 696 200 km2 and 1 854 400 km2 in China, respectively. The distribution of H. longicornis increased by 336 100 km2 and 367 300 km2 in 2050 and 2070 under the RCP 2.6 emissions scenario, and increased by 381 000 km2 and 358 000 km2 in 2050 and 2070 under the RCP 8.5 emissions scenario in China, respectively. CONCLUSIONS Climatic and environmental factors, such as precipitation, temperature and elevation, greatly affect the distribution of H. longicornis in China, and the suitable habitats of H. longicornis may expand in China under different climate patterns in future.

D J Cun

Q Wang

X Y Yao

B Ma

Y Zhang

L H Li

Potential suitable habitats of Haemaphysalis longicornis in China under different climatic patterns

不同气候模式下中国长角血蜱潜在适宜栖息地

Objective To analyze the changes of small molecular metabolites in the larvae of a deltamethrin-sensitive strain of Anopheles sinensis following exposure to deltamethrin, so as to provide the scientific basis for investigating the metabolic pathway and screening metabolic markers of deltamethrin in An. sinensis. Methods The 50% and 75% lethal concentrations (LC50 and LC75) of deltamethrin against the larvae of a deltamethrin-sensitive strain of An. sinensis were calculated in laboratory. The type and content of An. sinensis larvae metabolites were detected using high performance liquid chromatography and mass spectrometry (LC-MS/MS) following exposure to deltamethrin at LC50 and LC75 for 30 min and 24 h, and the changes of metabolites were analyzed. Results The LC50 and LC75 values of deltamethrin were 4.36 × 10-3 µg/mL and 1.12 × 10-2 µg/mL against thelarvae of a deltamethrin-sensitive strain of An. sinensis. Following exposure of the larvae of a deltamethrin-sensitive strain of An. sinensis to deltamethrin at LC50 and LC75 for 30 min, the differential metabolites mainly included organic oxygen compounds, carboxylic acid and its derivatives, fatty acyl and pyrimidine nucleotides, with reduced glucose levels. Following exposure for 24 h, the differential metabolites mainly included organic oxygen compounds, carboxylic acid and its derivatives, aliphatic acyl and purine nucleotides, with increased glucose level detected. Conclusions Carbohydrate, carboxylic acid and its derivatives, fatty acyls, amino acids and their derivatives may play important roles in deltamethrin metabolism in the larvae of a deltamethrin-sensitive strain of An. sinensis.

Y S Li

J X Tang

J L Li

C Liang

M H Zhang

J Y Wu

G X Wang

G D Zhu

J Cao

Study on emergency metabolic changes of Anopheles sinensis larvae following exposure to deltamethrin

中华按蚊幼虫暴露于溴氰菊酯后的应急代谢变化研究

Objective To construct a cDNA library of Sparganum mansoni and immunoscreen antigen candidates for immunodiagnosis of sparganosis mansoni. Methods Total RNA was extracted from S. mansoni, and reversely transcribed into cDNA, which was ligated into the phage vector. These recombinant vectors were packaged in vitro to construct the SMART cDNA library of S. mansoni. Then, the cDNA library was immunoscreened with sera from patients with sparganosis mansoni to yield positive clones. The inserted fragments of positive clones were sequenced and subjected to homology analyses, and the structure and functions of the coding proteins were predicted. Results The SMATR cDNA library of S. mansoni was successfully constructed. The titer of the cDNA library was 6.25 × 106 pfu/mL, with a recombinant efficiency of 100%, and the mean length of the inserted fragments in the library was larger than 1 100 bp. A total of 12 positive clones were obtained by immunoscreening, and were categorized into Sm-I (Sm60-1), Sm-II (Sm58-1), Sm-III (Sm20-1) and Sm-IV (Sm22-3), with 1 134, 1 063, 883 bp and 969 bp long inserted fragments. Their coding proteins were highly homologous with the Spirometra erinaceieuropaei antigenic polypeptide, cytoplasmic antigen, ribosomal protein S4-like protein and unnamed protein product, respectively. Conclusions A SMART cDNA library of S. mansoni has been successfully constructed and 4 categories of positive clones have been identified, which provides a basis for further studies on diagnostic antigens for sparganosis mansoni.

Y Lu

J X Chen

P Song

H Li

L Ai

Y C Cai

Y H Chu

S H Chen

Construction of a cDNA library for Sparganum mansoni and screening of diagnostic antigen cadidates

曼氏裂头蚴cDNA文库的构建及诊断抗原候选基因的筛选

OBJECTIVE To detect the expression of transforming growth factor-β1 (TGF-β1), p38MAPK and bone morphogenetic protein-7 (BMP-7) protein in the liver specimens of patients with hepatic alveolar echinococcosis, and to investigate the potential role of TGF-β1, p38MAPK and BMP-7 protein in hepatic fibrosis caused by hepatic alveolar echinococcosis. METHODS A total of 20 patients with hepatic alveolar echinococcosis were enrolled as study subjects, and hepatic specimens were sampled from the sites within 0.5 cm (Group A) and 0.5 to 1.5 cm from hepatic alveolar echinococcosis lesions (Group B), while normal liver specimens sampled from the sites 2 cm and greater from hepatic alveolar echinococcosis lesions served as controls (Group C). The fibrosis of liver specimens was pathological examined using HE and Masson staining, and the expression of TGF-β1, p38MAPK and BMP-7 protein was quantified in liver tissues using Western blotting. The associations of TGF-β1, p38MAPK and BMP-7 protein expression with hepatic fibrosis were assessed. RESULTS HE staining showed the malaligned structure of hepatocytes and destruction of the structure of hepatic lobules at various degrees in liver specimens in groups A and B, with hepatocyte degeneration, atrophy and necrosis, hyperplasia of fibrous tissues and eosinophilic granulocyte infiltration seen, while no abnormal pathological alterations of liver tissues, normal hepatocyte structure and morphology and uniform size, no malaligned structure of hepatocytes, clear structure of hepatic lobules, no or mild hepatocyte degeneration or necrosis, and no eosinophilic granulocyte infiltration were seen in Group C. Masson staining showed that there was hyperplasia of multiple fibrous connective tissues in the liver portal areas in groups A and B, with fibrosis seen in hepatic lobules, while no obvious pathological changes were seen in Group C. There were significant differences seen in TGF-β1 (P < 0.001), p38MAPK (P < 0.01) and BMP-7 protein (P < 0.05) expression in liver tissues in groups A, B and C, and higher TGF-β1, p38MAPK and BMP-7 protein expression was quantified in groups A and B than in Group C (all P values < 0.05), while greater TGF-β1, p38MAPK and BMP-7 protein expression was detected in Group B than in Group C (all P values < 0.05). The expression of TGF-β1, p38MAPK and BMP-7 protein correlated positively with the severity of hepatic fibrosis (r = 0.866, 0.702 and 0.801, all P values < 0.05), and there were significant differences in TGF-β1 (F = 72.580, P < 0.01), p38MAPK (χ2 = 31.705, P < 0.01) and BMP-7 protein expression (χ2 = 48.388, P < 0.01) among liver tissues with different degrees of fibrosis. The TGF-β1 protein expression correlated positively with p38MAPK and BMP-7 protein expression (r = 0.607 and 0.702, both P values < 0.001), and the BMP-7 protein expression also correlated positively with p38MAPK protein expression (r = 0.456, P < 0.001). CONCLUSIONS The interaction among TGF-β1, p38MAPK and BMP-7 jointly participates in the development of hepatic fibrosis induced hepatic alveolar echinococcosis.

T Cao

Y W Yang

X Yang

H H Zhu

[Expression and significance of TGF-β1, p38MAPK and BMP-7 protein in liver specimens of patients with alveolar hepatic echinococcosis].

[TGF-β1、p38MAPK 和 BMP-7 蛋白在泡型肝包虫病患者肝组织中的表达及意义]

OBJECTIVE To analyze the epidemiological characteristics and diagnosis of imported malaria before and after malaria elimination in Nanjing City of Jiangsu Province, so as to provide the scientific evidence for formulating the malaria control strategy after malaria elimination. METHODS Data pertaining to the epidemic situation and individual investigation of malaria in Nanjing City before (from 2012 to 2016) and after malaria elimination (from 2017 to 2020) were captured from the National Notifiable Communicable Disease Reporting System and the Information System for Parasitic Diseases Control and Prevention and were analyzed statistically. RESULTS A total of 178 malaria cases were reported in Nanjing City from 2012 to 2020, and all were imported cases. There were 99 malaria cases reported before malaria elimination in Nanjing City, including 78 cases with Plasmodium falciparum malaria (78.79%), 5 cases with P. vivax malaria (5.05%), 10 cases with P. ovale malaria (10.10%), 3 cases with P. malariae malaria (3.03%) and 3 cases with mixed infections (3.03%), and 79 malaria cases reported after elimination, including 63 cases with P. falciparum malaria (79.75%), 5 cases with P. vivax malaria (6.33%), 9 cases with P. ovale malaria (11.39%), 2 cases with P. malariae malaria (2.53%). There was no significant difference in the proportion of each type of malaria cases in Nanjing City before and after malaria elimination (χ2 =2.400, P > 0.05). Malaria cases mainly acquired Plasmodium infections in African regions, and no significant difference was seen in the proportion of malaria cases returning to Nanjing City from African countries before and after malaria elimination (χ2 = 0.093, P > 0.05). The number of malaria cases peaked in Nanjing City in January and during the period from May to July before elimination, and there was no apparent seasonal variation in the distribution of malaria cases after elimination. The proportion of malaria cases living in Nanjing City was significantly greater after malaria elimination than before elimination (72.15% vs. 55.56%; χ2 = 5.187, P = 0.023). The proportions of businessmen and international students were both 5.05% before malaria elimination, and increased to 15.19% and 13.92% after elimination, respectively (χ2 = 5.229 and 4.229, both P values < 0.05). The percentage of definitive diagnosis of malaria at initial diagnosis was 18.75% in county-level hospitals before malaria elimination and increased to 61.11% after elimination (χ2 = 6.275, P = 0.012), while the proportion of malaria cases with definitive diagnoses in county-level hospitals was 4.04% before malaria elimination and increased to 13.92% after elimination (χ2 = 5.562, P = 0.018). During the period from 2012 to 2020, the proportion of malaria cases with definitive diagnoses within 1 to 3 days post-admission increased from 27.27% in Nanjing City before malaria elimination to 45.57% after elimination (χ2 = 6.433, P = 0.011). CONCLUSIONS The epidemic situation of imported malaria remains serious in Nanjing City during the post-elimination stage, and malaria parasite infections predominantly occur in African regions. In addition, there are changes in regional and occupational distributions of malaria cases and the diagnostic capability of malaria increases in county-level hospitals in Nanjing City after malaria elimination. Further improvements in the malaria surveillance system and the diagnostic and treatment capability of malaria in medical institutions at each level are required to consolidate malaria elimination achievements in Nanjing City.

Y S He

Y Wang

Y J Li

C Y Xie

[Epidemic situation and diagnosis of imported malaria before and after malaria elimination in Nanjing City, Jiangsu Province].

[江苏省南京市消除疟疾前后输入性疟疾的疫情与诊断]

ISSN	1005-6661
h-index	18

Publication Information	Publisher: zhong guo xue xi chong bing fang zhi za zhi she，Publishing cycle: ，Journal Type: journal，Open Access Journals: No
Basic data	Year of publication: 2011，Proportion of original research papers: 0.00%，Self Citation Rate:N.A.， Gold OA Rate: 0.00%

Chinese Journal of Schistosomiasis Control

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